1. Field of the Invention
The present invention relates to novel retinyl carbonate derivatives. The invention also relates to the use of these compounds in or for the preparation of compositions intended in particular for preventing or combating acne and/or chronological or actinic ageing of the skin.
2. Discussion of the Background
Retinoid-based cosmetic and/or dermatological compositions have undergone considerable development in recent years. The reason for this is that it has been found that certain compounds of the retinoid family, derived from retinoic acid, are advantageous in skin care, in particular in the treatment of acne and for limiting, or even eliminating altogether, the effects of ageing on the skin such as wrinkles, a weathered appearance, yellowing, loss of elasticity, a ruddy complexion and dryness of the skin, as well as the appearance of blemishes.
These signs of ageing are all the more accentuated when the skin is frequently exposed to sunlight or is particularly sensitive to exposure to UV radiation. Thus, the effects of intrinsic ageing of the skin (age-related) and of light-induced ageing (due to exposure to sunlight) can be cumulative. The manifestations of ageing usually appear at an advanced age; however, their prevention should be undertaken from the start of adult life by suitable care treatments.
Treatment of the skin with compounds of the retinoid family forms part of these preventive or curative care treatments for the signs of ageing.
Among the compounds of the retinoid family, retinol, also known as vitamin A, is most particularly advantageous. The reason for this is that retinol is a natural endogenous constituent of the human body. It is also well tolerated when applied to the skin up to levels that are considerably higher than those for retinoic acid.
However, when it is introduced into a cosmetic composition intended for topical application, retinol degrades rapidly under the effects of light, oxygen, metal ions, oxidizing agents, water or, in particular, under the effect of elevated temperature. There is thus a need for compounds with retinoid-type activity which are more stable than retinol.
WO 95/16659 discloses conjugate compounds obtained from the reaction of retinoids with organic acids or derivatives of these acids. The retinoid, which may be retinol, retinal, retinoic acid or dehydroretinol, is conjugated to the acid derivative, which may be an aldehyde, a ketone, an alcohol, an ester, etc. via an ester, reverse ester, amide or ether bond. Among the very great number of compounds corresponding to this definition, only the ether obtained by reaction of retinol with the hydroxyl function of glycolic acid is described. In particular, no mention is made of retinyl carbonate derivatives.
Moreover, the publications from Svishchuk et al., "Preparation of .alpha.-tocopherol (Vitamin E) Ethers", Farm. Zh., 29(6), 36-8 (1974) and from Protopova et al., "Insecticidal Action of 6-hydroxychroman derivatives", Fiziol, Akt. Veshchestva, 7, 142-4 (1975) describe, respectively, a tocopheryl retinyl carbonate and an analogous compound in which the side chain of the tocopheryl radical is slightly modified. However, these compounds are not intended for cosmetic use.